1. Technical Field related to the Invention
The present invention relates to a deep fat fryer for cooking foodstuffs in cooking oil supplied and heated in a frypot.
2. Description of the Related Art
A deep fat fryer of such a conventional type comprises, as shown in FIG. 9, a frypot 1 incorporating a box-like form of container of which the top side is open and the bottom side is closed and an apron 8 mounted to the top of the frypot 1. The frypot 1 comprises a pair of opposed joint sidewalls 2 arranged parallel to each other and a pair of opposed bending sidewalls 3. The bending sidewall 3 comprises an upper sidewall portion 4 at the upper side spaced widely from its counterpart, a lower sidewall portion 5 at the lower side spaced from its counterpart by a distance smaller than that of the upper sidewall portion 4, a sloping sidewall portion 6 connecting the upper sidewall portion 4 and the lower sidewall portion 5 to each other, and an bottom sidewall portion 7 having an arcuate form in cross section bent inwardly of the lower sidewall portion 5. The frypot 1 is commonly fabricated, as shown in FIG. 10, by punching and pressing metal sheets to form the two opposed joint sidewalls 2 having a symmetrical shape for sandwiching between the two opposed bending sidewalls 3 and then assembling and welding the joint sidewalls 2 and the bending sidewalls 3 securely. The frypot 1 can be heated by the combustion on burners 9 which are provided so as to sandwich the lower sidewall portions 5 of the opposed bending sidewalls 3. In other words, the lower sidewall portions 5 are heating surfaces (heat dissipating sides).
The shape of the bending sidewall 3 is so designed that the frypot 1 is minimized in the volume of oil and increased in the heat absorbing area. The lower narrow part of the frypot 1 sandwiched between the two lower sidewall portions 5 is provided for collecting the cooking debris of foodstuffs and preventing the deterioration of the oil.
Problem that the Invention is to solve
However, the lower sidewall portions 5 of the bending sidewalls 3 which are the heating surfaces develop thermal expansion and contraction due to repeated cycles of heating and cancellation of the burner 9 and will hence receive thermal stress particularly at their joint to the joint sidewalls 2 and permit the generation of flaws or cracks.